Health care institutions (e.g., hospitals, clinics, doctor's offices) may have multiple computer software systems to provide a variety of services. For example, a hospital may use an administrative system for admission of patients. The administrative system may facilitate taking and managing information such as patient name, insurance information, etc. The hospital may have a billing system to generate invoices and send bills to insurance companies, and a lab system to manage diagnostic tests. Sometimes, the services provided by another system may be needed. For example, the administrative system may need to invoke services provided in the billing system to generate bills and services provided in the lab system to schedule diagnostic tests. There is a need to integrate diverse systems, such as an administrative system, a billing system and a lab system, by a communication framework.